In criminal cases, it is advised to get the lawyer involved since the start of the suspicions, in the frame of the police custody most of the time, because the innocence or the guilt of the person is drawn since that very moment.
The intervention of the lawyer has the advantage of moderating the brutality of the police investigations, and he may invalidate the coercive measures if there would be some procedural defects.
Then, when the case is sent to the criminal court, the lawyer may defend his client, either as an accused or as a victim, by pleading the case.